The first of a group of Greenpeace activists arrested for an Arctic oil protest and later freed by a Russian amnesty has boarded a train out of the country.

Dima Litvinov has returned home to Finland three months after he and 29 others were arrested for staging a protest at an Arctic oil rig three months ago.

Around half of the group of 30 have now been granted exit visas from Russia after charges against them of hooliganism were dropped under a wide-ranging amnesty, which also saw members of the punk band Pussy Riot freed.

Activists showed off their passports stamped with transit visas to journalists outside the migration services offices in Saint Petersburg, Russia's second city, where they have been staying for over a month.

"Fourteen people have been given a visa," Greenpeace spokesman Arin de Hoog told AFP.

"They will depart from Russia in the coming days."

Mr Litvinov says he is proud of what he did, but is looking forward to getting home to his bed, wife and kids.

Greenpeace says the other activists, including an Australian Colin Russell and two Australian residents, will leave Russia in the coming days.

Russian border guards boarded the Greenpeace ship Arctic Sunrise on September 19 and had it towed to the Arctic port of Murmansk.

The crew, which included two journalists, were accused of piracy and hooliganism, and spent almost two months in jail in and around the Arctic city of Murmansk.

In November, they were put on a train and moved to Saint Petersburg.

The charge of piracy, punishable by up to 15 years in prison, was eventually dropped, leaving the lesser accusation of hooliganism, which carries a punishment of up to seven years.

Russian president Vladimir Putin has said that the activists, several of which attempted to scale energy giant Gazprom's Prirazlomnaya oil rig in the Barents sea, broke the law and were seeking publicity but were "not pirates."

Several western leaders, including German chancellor Angela Merkel, expressed concern over the activists' detention, and celebrities including former Beatle Paul McCartney had pressed for their release.

A UN maritime court in Germany also ruled in favour of a complaint lodged by the Netherlands and ordered Russia to release the crew and the Dutch-flagged ship, but Russia ignored the decision.